甘肃省天水地区上第三系含坡缕石白土的研究   总被引：1，自引：0，他引：1  

杨雅秀  张小毅 《岩石学报》1991,7(1):70-78

天水地区新第三纪湖相白土除含少量碎屑矿物石英、长石外,主要由伊利石、绿泥石、蒙皂石等粘土矿物及白云石、方解石等碳酸盐矿物组成。北部地区含有坡缕石,最多约40％,南部含有方沸石。白土中的粘土和碳酸盐矿物颗粒细小,有序度差。坡缕石由胶体结晶,或由碎屑云母转变而成。白土的形成温度约20～50℃,介质是咸水-半咸水,具碱性。当B、Sr/Ca值及盐度较高,而Sr/Ba、Br/Cl、δ~(18)O值及温度较低时,有利於形成坡缕石。  相似文献   

浅层地震勘探在滇西第三系盆地探查铀矿床的应用及效果     

董兆麟 《铀矿地质》1990,6(5):291-296

通过对方法可行性试验,确认在滇西第三系盆地中应用浅层地震反射波方法,探查100—400m深度的基底形态、构造及对盖层分层的有效性。试验采用McSEIS-1500地震仪,选择合适的激发条件,根据工作区有效波和干扰波的特点,研究并采取了有效的野外技术措施,达到提高S/N比,突出有效波的目的。  相似文献   

安阳上第三系化学矿物指标显示物源区大地构造          下载免费PDF全文

尚彦军  蒋毅  高强  李严严 《地质科学》2016,(3):779-793

南水北调（中线）安阳主干渠段施工过程中开挖出大量成熟度低且受近源构造影响较大的河湖相沉积岩。对现场采集的上第三系岩石样品开展了化学成分、 岩石骨架成分测试。利用Dickinson法和化学指标法, 研究得到安阳主干渠段西部物源区属于被动陆缘, 在上新世晚期向活动陆缘变化的认识。同期构造活动强烈的克什米尔N—J引水隧洞段的沉积岩, 属于岛弧和活动陆缘的大地构造背景。本文结果丰富了构造稳定和活跃区新近纪沉积构造背景认识, 可为喜马拉雅运动以来不同构造活动背景下的岩石组分和化学指标特征提供参考。  相似文献   

中国近海早第三纪海侵层序及地层对比   总被引：1，自引：0，他引：1  

彭世福 《海洋地质与第四纪地质》1992,(1)

中国近海各盆地,据古生物群及沉积特征,在早古新世为陆相沉积,至中晚古新世时为第Ⅰ海侵期。早始新世时为海退期,至中晚始新世为第Ⅱ海侵期。早、中渐新世时为海退期,晚渐新世为第Ⅲ海侵期。在论证地层时代时结合海侵的划分,提出新的见解。海相夹层可作为地层对比的重要标志层。  相似文献   

Cretaceous-Eogene Ostracod Assemblages in Henan and Their Evolutionary Features     

Zhang Shen Jidong Oil Exploration &. Development Corp.  Tanghai  Hebei Fei Zhenbi 《《地质学报》英文版》1995,69(1):99-110

This paper studies a large number of Cretaceous-Eogene ostracod fossils in the Meso-Cenozoic Nanyang, Zhoukou, Rendian, Luoyang, Lingbao, Tantou and Kaifeng basins of Henan. Eight ostracod assemblages have been recognized. This paper discusses their geographical distribution and geological ages as well as their features and evolutional trends. Besides, it also deals with the palaeoclimate under which the various assemblages lived and the significance in petroleum exploration.  相似文献   

四川雅安地区早第三纪地层     

赵兵  李勇 《地层学杂志》1995,19(2):96-103

下第三系名山组广泛分布于雅安地区，地层出露良好。本文简要介绍雅安国光山背斜东西两翼新测的地层剖面，将名山组（包括芦山组）划分成４段（砂岩粉砂岩段、粉砂岩泥岩泥灰岩段、泥岩粉砂岩段、泥岩段），并将芦山组归于名山组上部（Ⅳ段），从而取消该名称，综述了岩石组合特征、沉积环境，进行了生物地层和年代地层划分。  相似文献   

Anomalous low palaeomagnetic inclinations from Oligocene—Lower Miocene red beds of the south-west Tien Shan, Central Asia     

Annick Chauvin  Herve Perroud  Mikhail L. Bazhenov 《Geophysical Journal International》1996,126(2):303-313

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Selective dissolution of late cretaceous and earliest tertiary calcareous nannofossils: Experimental evidence     

H.R. Thierstein 《Cretaceous Research》1980,1(2):165-176

The effects of carbonate dissolution on the taxonomic composition of ancient nannofossil assemblages were investigated by deploying them on a deep mooring at depths of 1039 m–5500 m for 117 days in the Sargasso Sea. The relative proportions of only a few taxa change significantly with increasing dissolution: Cruciplacolithus primus is by far the most susceptible and Micula staurophora by far the most resistant species. The average dissolution indices calculated for the deployed assemblages closely follow the gradients of other dissolution indicators in the North Atlantic.  相似文献   

Résultats préliminaires sur la sédimentation pélagique de l'Atlantique tropical au Crétacé et au Tertiaire (plateau de Demerara,Leg ODP 207)     

Taniel Danelian  Laurence Le Callonnec  Jochen Erbacher  David C. Mosher  Mitchell J. Malone  Debora Berti  Karen L. Bice  Helen Bostock  Hans-Jürgen Brumsack  Astrid Forster  Felix Heidersdorf  Jorijntje Henderiks  Thomas J. Janecek  Christopher Junium  Ken MacLeod  Philip A. Meyers  Jörg H. Mutterlose  Hiroshi Nishi  Christine Glatz 《Comptes Rendus Geoscience》2005,337(6):609-616

Five sites located on a bathymetric transect of the distal Demerara Rise were studied by ODP Leg 207. Albian sediments of essentially terrigenous nature (clay, siltstone, sandstone) are the oldest drilled stratigraphic levels and form apparently the top of the synrift sequence. They are overlain by Cenomanian to Santonian finely laminated black shales, rich in organic matter of marine origin, which accumulated on a thermally subsiding ramp. Early Campanian hiatuses are thought to be the result of final disjunction of Demerara Rise (South America) from Africa and the onset of deep water communication between the two Atlantic basins (south and central). The overlying Uppermost Cretaceous–Oligocene chalk includes rich and diversified calcareous plankton assemblages, as well as two radiolarian-rich intervals (Late Campanian and Middle Eocene). A complex erosional surface developed during the Late Oligocene–Early Miocene. Sedimentation was impeded since then on the intermediate and deep sites of Demerara Rise, possibly due to the action of deep submarine currents. To cite this article: T. Danelian et al., C. R. Geoscience 337 (2005).  相似文献   

Tertiary geodynamics of Sakhalin (NW Pacific) from anisotropy of magnetic susceptibility fabrics and paleomagnetic data   总被引：1，自引：0，他引：1  

Richard Weaver  Andrew P Roberts  Rachel Flecker  David I.M Macdonald   《Tectonophysics》2004,379(1-4):25-42

Sakhalin has been affected by several phases of Cretaceous and Tertiary deformation due to the complex interaction of plates in the northwest Pacific region. A detailed understanding of the strain is important because it will provide constraints on plate-scale processes that control the formation and deformation of marginal sedimentary basins. Anisotropy of magnetic susceptibility (AMS) data were obtained from fine-grained mudstones and siltstones from 22 localities in Sakhalin in order to provide information concerning tectonic strain. AMS data reliably record ancient strain tensor orientations before significant deformation of the sediments occurred. Paleomagnetically determined vertical-axis rotations of crustal rocks allow rotation of the fabrics back to their original orientation. Results from southwest Sakhalin indicate a N035°E-directed net tectonic transport from the mid-Paleocene to the early Miocene, which is consistent with the present-day relative motion between the Okhotsk Sea and Eurasian plates. Reconstruction of early–late Miocene AMS fabrics in east Sakhalin indicates a tectonic transport direction of N040°E. In west Sakhalin, the transport direction appears to have remained relatively consistent from the Oligocene to the late Miocene, but it has a different attitude of N080°E. This suggests local deflection of the stress and strain fields, which was probably associated with opening of the northern Tatar Strait. A northward-directed tectonic transport is observed in Miocene sediments in southeast Sakhalin, mid-Eocene sediments in east Sakhalin, and in Late Cretaceous rocks of west and northern Sakhalin, which may be associated with northwestward motion and subduction of the Pacific Plate in the Tertiary period. The boundaries of the separate regions defined by the AMS data are consistent with present-day plate models and, therefore, provide meaningful constraints on the tectonic evolution of Sakhalin.  相似文献